GW24-e3684 Observing canines’ endothelial by electron microscopy after closure surgery of ASD which used large occluder

Objectives Discussing what causes endothelialisation insufficiency, then we can offer factual basis to closure surgery of ASD. Methods 18 canines were randomly divided into three groups, made 6 mm diameter atrial septal defect for each canine, what was guided by transthoracic echocardiography, then placed in different types of occluder in three group of canines, routinely given anti-infective and anticoagulant therapy after operation, 14 months later, put them to death and got the heart, separated the newborn endothelial tissue which was on the occluder in electron microscopy. Results Operations went on well, after 14 months, we could see if the occluder diameter was more closer with the defect diameter, the more endothelial tissue covered as well as grew more regularly, we can see endothelialisation of insufficiency in the group of too large occluder. Conclusions During ASD surgery, too large occluder can lead to endothelialisation of insufficiency, so we should choose the occluder whose diameter is close to the defect as much as possible, which is more conducive to the endothelial tissue regeneration.